China’s new mega dam on the Yarlung Zangbo River sparks fears of an India-China water conflict, prompting India to fast-track its own dam project. India fears China’s mega dam on the Yarlung Zangbo River in Tibet, announced in December 2024, could reduce Brahmaputra River flows by up to 85% during dry seasons, prompting New Delhi to accelerate its Upper Siang Multipurpose Storage Dam project to mitigate the India-China water conflict.
Why It Matters for South Asia
The India-China water conflict over the Brahmaputra threatens South Asia’s water security, affecting over 100 million people in India and Bangladesh. This escalating geopolitical tension could disrupt regional agriculture, economies, and stability, underscoring the need for cooperative water management in a water-stressed region.
China’s Mega Dam and India’s Response
In December 2024, China announced plans to build the world’s largest hydropower dam in Tibet’s Medog county, just before the Yarlung Zangbo River enters India as the Brahmaputra. Costing USD 170 billion, the dam, which broke ground in July 2025, aims to generate 300 billion kilowatt-hours annually, surpassing China’s Three Gorges Dam. India’s government analysis, corroborated by four sources, estimates the dam could divert 40 billion cubic metres of water, reducing flows at a key border point by over a third, particularly during non-monsoon months, according to Reuters.
To counter this, India is fast-tracking the Upper Siang Multipurpose Storage Dam in Arunachal Pradesh, with a projected 14 billion cubic metres (BCM) storage capacity. This dam aims to mitigate water scarcity, ensuring an 11% supply reduction for Guwahati’s water-intensive industries and farming, compared to 25% without it. It could also absorb excess water from potential Chinese dam breaches, with India considering keeping 30% of the dam empty for flood surges.
India-China Water Conflict: Regional and Environmental Concerns
The India-China water conflict is heightened by China’s strategic location as the upper riparian state and its territorial claims in Arunachal Pradesh. Indian officials, including Arunachal Pradesh Chief Minister Pema Khandu, have called the dam a “water bomb,” fearing Beijing could weaponise water flows during tensions. The absence of a binding bilateral water-sharing treaty, unlike India’s agreements with Pakistan and Bangladesh, exacerbates mistrust. A 2002 hydrological data-sharing agreement exists, but China suspended it during the 2017 Doklam standoff, highlighting its vulnerability to geopolitical strains.
Environmental and Social Impacts
Both dams pose significant environmental risks in the seismically active Himalayan region. Experts, including Sayanangshu Modak from the University of Arizona, warn that China’s dam, built in a zone prone to landslides and glacial lake outburst flooding, could endanger downstream communities. India’s Upper Siang project faces local opposition from the Adi community, with at least 16 villages, affecting 10,000 people, at risk of submersion. Community leader Odoni Palo Pabin stated, “We will fight the dam to death,” citing threats to livelihoods from paddy and fruit farming. Despite this, three villages recently allowed survey work after compensation discussions, with the state allocating USD 3 million for education and infrastructure incentives.
China’s Foreign Ministry claims the dam underwent rigorous safety and environmental research, asserting no adverse impact on downstream countries. However, India’s Foreign Minister S. Jaishankar raised concerns with his Chinese counterpart on August 18, 2025, urging protection of downstream interests.
Background
The Brahmaputra, originating at Tibet’s Angsi Glacier, sustains over 130 million people across China, India, and Bangladesh. The India-China water conflict is part of a broader rivalry, including border disputes along the Line of Actual Control. China’s dam-building history, such as 11 dams on the Mekong River, has drawn criticism for unilateral actions, with India and Bangladesh often uninformed. India’s own water disputes, notably with Pakistan over the Indus Waters Treaty, highlight regional complexities, with New Delhi rejecting a 2025 international ruling to maintain flows to Pakistan.
What’s Next
India’s Upper Siang dam, if approved, may take a decade to complete, potentially lagging behind China’s project, expected to generate power by the early 2030s. Both nations need to establish joint monitoring and data-sharing mechanisms to mitigate the India-China water conflict and ensure regional water security.
Published in SouthAsianDesk, August 25th, 2025
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